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| author |   Jann Horn <jannh@google.com> | 2018-08-31 21:41:51 +0200 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2018-09-06 14:33:12 +0200 |
| commit | 9fe6299dde587788f245e9f7a5a1b296fad4e8c7 (patch) | |
| tree | 45fd4582b522ebfe51c990470f409ba66ba22f17 /arch/x86/kernel/process_64.c | |
| parent | x86/tsc: Prevent result truncation on 32bit (diff) | |
| download | linux-dev-9fe6299dde587788f245e9f7a5a1b296fad4e8c7.tar.xz linux-dev-9fe6299dde587788f245e9f7a5a1b296fad4e8c7.zip | |
x86/process: Don't mix user/kernel regs in 64bit __show_regs()
When the kernel.print-fatal-signals sysctl has been enabled, a simple
userspace crash will cause the kernel to write a crash dump that contains,
among other things, the kernel gsbase into dmesg.
As suggested by Andy, limit output to pt_regs, FS_BASE and KERNEL_GS_BASE
in this case.
This also moves the bitness-specific logic from show_regs() into
process_{32,64}.c.
Fixes: 45807a1df9f5 ("vdso: print fatal signals")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180831194151.123586-1-jannh@google.com
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kernel/process_64.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index a451bc374b9b..ea5ea850348d 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -62,7 +62,7 @@ __visible DEFINE_PER_CPU(unsigned long, rsp_scratch); /* Prints also some state that isn't saved in the pt_regs */ -void __show_regs(struct pt_regs *regs, int all) +void __show_regs(struct pt_regs *regs, enum show_regs_mode mode) { unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L, fs, gs, shadowgs; unsigned long d0, d1, d2, d3, d6, d7; @@ -87,9 +87,17 @@ void __show_regs(struct pt_regs *regs, int all) printk(KERN_DEFAULT "R13: %016lx R14: %016lx R15: %016lx\n", regs->r13, regs->r14, regs->r15); - if (!all) + if (mode == SHOW_REGS_SHORT) return; + if (mode == SHOW_REGS_USER) { + rdmsrl(MSR_FS_BASE, fs); + rdmsrl(MSR_KERNEL_GS_BASE, shadowgs); + printk(KERN_DEFAULT "FS: %016lx GS: %016lx\n", + fs, shadowgs); + return; + } + asm("movl %%ds,%0" : "=r" (ds)); asm("movl %%cs,%0" : "=r" (cs)); asm("movl %%es,%0" : "=r" (es)); |